1. Field of the Invention
The present invention relates generally to tube supporting members for heat exchangers such as condensers, evaporators and oil coolers used in automotive vehicles. More particularly, the present invention relates to an endsheet for use in a fin and tube type heat exchanger wherein the endsheet provides increased support for the heat exchanger tubing.
2. Disclosure Information
Fin and tube type heat exchanger are commonly used in vehicle, industrial and residential environments for heating and cooling purposes. Typically, these heat exchanger utilize a plurality of tubes to form a condenser or the like by having the fluid pass through a plurality of U-shaped tubes. The number of U-shape tubes depends on a thermal capacity requirements of the fin and tub heat exchanger. A manifold interconnects these tubes so that the fluid can flow through the tubes.
Endsheets or headers support the heat exchanger tubes and mount the heat exchanger to the vehicle structure. Typical prior art endsheets, such as shown in U.S. Pat. No. 5,190,101, assigned to the assignee of the present invention, are stamped from a metal blank and include apertures through which the tubes are passed. The apertures provide little support for the tubing, the support being equal to the thickness of the endsheet. These prior art endsheets have worked well in the past for heat exchanger below a critical size. However, when the heat exchanger becomes larger and heavier or the application in which the heat exchanger used is subject to severe stresses, the prior art endsheets may not provide enough support for the tubes, resulting in leakage at the tube-manifold interface. Therefore, it would be advantageous to provide an endsheet or tube support member which provides increased support for the tube and fin exchanger.
U.S. Pat. No. 5,181,561 proposes one type of type supporting member for a heat exchanger used in the aircraft industry. The '561 patent discloses a stiffener plate having a plurality of openings for receiving the tubes therethrough. Each opening is in the form of an integral short-length tubular ferrule portion of internal diameter slightly greater than the external diameter of the tube. The ferrule supports the tubular member. Each ferrule of the '561 patent is formed through an extrusion process and includes a smooth, continuous radius for the tube to pass through. This smooth, continuous radius of the stiffener plate in the '561 patent cannot be used however in certain types of automotive heat exchangers. In the manufacturing of certain automotive type heat exchanger, such as condensers, it is necessary that a mandrel be inserted through the tube after the tube has been placed through the endsheet to expand the diameter of the tube to increase the tube-fin contact area. It has been found that using a stiffener plate, such as that in the '561 patent with a ferrule having a smooth continuous radius, allows the tubing to slide through the endsheet during the expansion process, and thus destroying the condenser during the manufacturing process. Therefore, it would be advantageous to provide a tubular support member, such as an endsheet for condenser, which would allow for increased support of the tubular members and which does not allow the tubing to slide therethrough during the manufacturing process.